The genus Mycobacterium includes highly successful pathogens e.g. Mycobacterium tuberculosis and Mycobacterium leprae, the etiological agents of tuberculosis and leprosy, respectively. The M. tuberculosis (Mtb) is one of the most successful human pathogens and estimations suggest that one third of the human population carry this bacteria. Other Mycobacterium species worth mentioning are Mycobacterium marinum (Mm), Mycobacterium avium and Mycobacterium ulcerans. 
Today approximately eight million people per year develop active disease and two million die. Pathogenic mycobacteria have the ability to persist for a long time in the host without causing any symptoms. This latency poses an additional hidden threat to human health but is not clearly understood. Mycobacteria can colonize their hosts without the hosts showing any adverse signs. For example, billions of people around the world are infected with M. tuberculosis but will never know it because they will not develop symptoms.
Mycobacterial infections are notoriously difficult to treat. The organisms are hardy due to their cell wall, which is neither truly Gram negative nor positive, and unique to the family, they are naturally resistant to a number of antibiotics that work by destroying cell walls, such as penicillin. Most mycobacteria are susceptible to antibiotics e.g. clarithromycin, isoniazid and rifamycin, but antibiotic-resistant strains are known to exist, and the emergence of multi resistant strains is an increasing problem.
An attenuated strain of Mycobacterium bovis is currently the most widely used and safest attenuated human vaccine, but controversy concerning its efficacy has emerged.
Consequently, there is a need for improved methods and medicaments to prevent and treat diseases which are caused by Mycobacteria.